Organic devices include organic electronic devices and organic opto-electronic devices. Organic electronic devices are devices having an organic active layer to control electron flows in the devices, such as organic thin film transistors. Organic opto-electronic devices have an organic active layer either to convert photon energy into electron energy or to convert electron energy into photon energy. Examples of opto-electronic devices are organic solar cells, organic photodetectors, and organic light-emitting diodes (OLEDs). Organic devices are becoming increasingly desirable for many potential applications. For example, OLEDs, as described by Tang in commonly assigned U.S. Pat. No. 4,356,429, are commercially attractive because they offer the promise of low cost fabrication of high density pixel displays exhibiting bright electroluminescence (EL) with long lifetime, high luminous efficiency, low drive voltage, and wide color range.
A typical OLED includes two electrodes and one organic EL unit disposed between the two electrodes. The organic EL unit commonly includes an organic hole-transporting layer (HTL), an organic light-emitting layer (LEL), and an organic electron-transporting layer (ETL). One of the electrodes is the anode, which is capable of injecting positive charges (holes) into the HTL of the EL unit. The other electrode is the cathode, which is capable of injecting negative charges (electrons) into the ETL of the EL unit. When the anode is biased with a certain positive electrical potential relative to the cathode, holes injected from the anode and electrons injected from the cathode can recombine and emit light from the LEL.
In order to facilitate hole injection from the anode into the HTL, thereby reducing the drive voltage of the OLEDs, it is often useful to provide a hole-injecting layer (HIL) in the organic EL unit. Suitable materials for use in HIL include porphyrinic compounds as described by VanSlyke et al. in U.S. Pat. No. 4,720,432, such as copper phthalocyanine (CuPc). Suitable materials for use in HIL also include some aromatic amines as described by Imai et al. in U.S. Pat. No. 5,256,945, such as 4,4′,4″-tris[(3-ethylphenyl)phenylamino]triphenylamine (m-TDATA). Alternative hole-injecting materials reportedly useful in OLEDs are described in EP 0 891 121 A1, EP 1 029 909 A1, U.S. Pat. No. 6,423,429, U.S. Pat. No. 6,720,573, and U.S. Patent Application Publication 2004/0113547 A1.
Moreover, in order to have an improved hole injection and improved electroluminescence (EL) performance in OLEDs, Hung et al. in U.S. Pat. No. 6,208,075 B1 and Hatwar et al. in U.S. Pat. No. 6,127,004 disclosed a method of forming a fluorocarbon polymer layer as an HIL layer (or as an electrode modification layer) on an indium-tin-oxide (ITO) anode surface. The fluorocarbon polymer layer contains a CFx as a repeating unit, and is denoted as (CFx)n layer, wherein “x” and “n” are integers, x<4 and n>1. The (CFx)n layer is formed by a plasma treatment in a vacuum chamber containing CHF3 gas. The OLEDs containing (CFx)n layer on the anode surface do exhibit improved voltage performance and operational lifetime.
Although (CFx)n layer is an excellent HIL or electrode modification layer, it needs a separated plasma deposition chamber to prepare this (CFx)n layer and it is difficult to form this (CFx)n layer with identical thickness from one substrate to another substrate causing drive voltage deviation from one device to another device. Moreover, in some cases, this (CFx)n layer is contaminated when exposed to air during the transfer of the substrate to another deposition chamber for organic layer deposition.
In order to simplify the fabrication of organic devices, to improve manufacturing capability, and to enhance device performance, it is necessary to find an improved fluorocarbon compound layer as an electrode modification layer in the devices.